1. Field of the Invention
The present invention relates to a film deposition apparatus for depositing a film on a substrate by carrying out plural cycles of supplying in turn at least two reaction gases to the substrate in order to form plural layers of a reaction product, thereby depositing a thin film.
2. Description of the Related Art
As a film deposition technique in a semiconductor fabrication process, there has been known a film deposition method, in which a first reaction gas is adsorbed on a surface of a semiconductor wafer (referred to as a wafer hereinafter) under vacuum and then a second reaction gas is adsorbed on the surface of the wafer in order to form one or more atomic or molecular layers through reaction of the first and the second reaction gases on the surface of the wafer, and such an alternating adsorption of the gases is repeated plural times, thereby depositing a film on the wafer. This method is called a so-called Atomic Layer Deposition (ALD) or Molecular Layer Deposition (MLD), and is advantageous in that the film thickness can be controlled at higher accuracy by the number of times of supplying in turn the gases, and in that the deposited film can have excellent uniformity over the wafer. Therefore, this deposition method is thought to be promising as a film deposition technique that can address further miniaturization of semiconductor devices.
As such a deposition method, a deposition method using a single-wafer deposition apparatus having a vacuum chamber and a shower head at an upper center portion of the vacuum chamber has been under consideration, in which the reaction gases are introduced into the chamber from the shower head, and unreacted gases and by-products are evacuated from a bottom portion of the vacuum chamber. When such a deposition chamber is used, it takes a long time for a purge gas to purge the reaction gases when the first reaction gas and the second reaction gas are switched, and in addition the number of cycles may reach several hundred, resulting in an extremely long process time. Therefore, a deposition method and apparatus that enable high throughput is desired.
Under these circumstances, film deposition apparatuses have been proposed that include a vacuum chamber, a wafer supporting member (or a turntable) that holds plural wafers along a rotation direction, which is provided in the vacuum chamber, first and second reaction gas nozzles that oppose the wafer supporting member and are arranged at equal angular intervals, and separation gas nozzles that are arranged between the first and the second reaction gas nozzles. In such a deposition apparatus, the first and the second reaction gases are concurrently supplied and the wafer supporting member by which the wafers are supported is rotated, thereby carrying out the film deposition method.